(a) Field of the Invention
The present invention relates to an image information processing device, and particularly to an image signal selecting device adapted to remove unnecessary image signals stored during a transition and to supply only necessary image signals to a signal processing system, in the case of picking up the image of an object having a substantially stationary state and a transitionary state with a storage type image pickup device.
(b) Description of the Prior Art
Various kinds of image pickup tube or solid state image pickup devices used as an image pickup device exist in which an electric signal of a size proportional to the amount of light incident upon the light receiving surface of the image pickup device for a fixed time (a storage time) is issued as an output signal. When the light intensity distribution of an object image is converted into an electric signal by means of this kind of image pickup device, if the position of the object image is changed on the light receiving surface within the storage time, the output signal will be issued in accordance with a light intensity distribution formed by two overlapping independent light intensity distributions and therefore, the image signal will not present a correct object image.
In order to obtain a correct image signal by picking up an object image which repeats a substantially stationary state and a fluctuant state on the light receiving surface of the image pickup device, it is necessary to use only the output signal stored in the image pickup device during the substantially stationary state without picking up the output signal including therein such fluctuant state as the shift of the image position or the like.
In a device processing an image signal by using a signal processing device such as a micro-computer or the like, it is possible to take all output signals from the image pickup device into the signal processing device and to perform a selection as to whether the signal taken in should be picked up or not, by means of software, in the signal processing device. However, if the above mentioned processing method is used, there is a disadvantage that many memories are required to momentarily store the output signals from the image pickup device. To the contrary, it is possible to arrange the software so as to take only necessary image signals into the signal processing device. In this case, however, the operation for making the change of image, picking-up of image and taking-into of signals must synchronize. That is, a timing operation must be performed by means of software. This will complicate the software program.